全文获取类型
收费全文 | 2251篇 |
免费 | 187篇 |
国内免费 | 300篇 |
专业分类
化学 | 1162篇 |
晶体学 | 24篇 |
力学 | 156篇 |
综合类 | 8篇 |
数学 | 744篇 |
物理学 | 644篇 |
出版年
2024年 | 8篇 |
2023年 | 60篇 |
2022年 | 98篇 |
2021年 | 95篇 |
2020年 | 96篇 |
2019年 | 58篇 |
2018年 | 69篇 |
2017年 | 99篇 |
2016年 | 100篇 |
2015年 | 97篇 |
2014年 | 143篇 |
2013年 | 232篇 |
2012年 | 243篇 |
2011年 | 242篇 |
2010年 | 188篇 |
2009年 | 173篇 |
2008年 | 105篇 |
2007年 | 134篇 |
2006年 | 99篇 |
2005年 | 73篇 |
2004年 | 39篇 |
2003年 | 36篇 |
2002年 | 43篇 |
2001年 | 48篇 |
2000年 | 26篇 |
1999年 | 37篇 |
1998年 | 22篇 |
1997年 | 7篇 |
1996年 | 16篇 |
1995年 | 12篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
排序方式: 共有2738条查询结果,搜索用时 31 毫秒
1.
Numerical Algorithms - In this paper, we combine the ideas of multilevel augmentation methods for solving integral equations and the shifted-inverse power method to develop a new multilevel... 相似文献
2.
Czechoslovak Mathematical Journal - The irregularity of a graph G = (V, E) is defined as the sum of imbalances ∣du ? dv∣ over all edges uv ∈ E, where du denotes the degree... 相似文献
3.
Schmalian Misha Suris Yuri B. Tumarkin Yuriy 《Mathematical Physics, Analysis and Geometry》2021,24(4):1-17
Mathematical Physics, Analysis and Geometry - In this paper, we develop the dressing method to study the modified Camassa-Holm equation with the help of reciprocal transformation and the associated... 相似文献
4.
Lin Yu Wu Yeyu Tan Xuecai Wu Jiawen Huang Kejing Mi Yan Ou Panpan Wei Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin... 相似文献
5.
6.
独立高校数学课程的开设旨在让学生掌握数学知识的基础上,提高数学应用能力.然而现行的考核方式存在重考试结果,轻学习过程等问题.从传统考核方式入手,指出其不足之处,基于模糊综合评判法建立新型评价体系和数学模型,通过试点运行验证了新的考核方式的可行性、客观性、合理性和科学性. 相似文献
7.
In this paper, sufficient conditions for the global asymptotic stability of a broad family of periodic impulsive scalar delay differential equations are obtained. These conditions are applied to a periodic hematopoiesis model with multiple time-dependent delays and linear impulses, in order to establish criteria for the global asymptotic stability of a positive periodic solution. The present results are discussed within the context of recent literature. In conclusion, when compared with previous works, not only sharper stability criteria are obtained here, even for models without impulses, but also the usual constraints imposed on the linear impulses are relaxed. 相似文献
8.
Numerical Algorithms - A singularly perturbed Volterra integro-differential equation with an integrable singularity in the integral term is considered. The upwind difference method is used to... 相似文献
9.
Qi-Jun Li Ya-Jie Ren Qin Xie Min Wu Hua-Xing Feng Li-Mei Zheng Hua-Xin Zhang Jin-Qiao Long Tian-Shun Wang 《应用有机金属化学》2020,34(10):e5813
Two nickel complexes, [Ni(tpen)](ClO4)2.0.5CH3COCH3 ( 1 ) and [Ni(tpbn)](ClO4)2 ( 2 ), of tetrapyridyl ligands N,N,N′,N′-tetrakis(2-pyridyl-methyl)-1,2-ethanediamine (tpen) and N,N,N′,N′-tetrakis(2-pyridyl-methyl)-1,4-butanediamine (tpbn) were prepared and their catalysis for water oxidation reaction (WOR) studied. In 0.1 M phosphate buffer solution (PBS) of pH 8.0, complex 1 is a homogeneous molecular catalyst with an overpotential of ~440 mV and a Faradaic efficiency of 89%. At pH ≥ 9.0, complex 1 degraded gradually during the catalytic process and formed NiOx composite (nickel oxide with general formula NixOyHz) active for WOR. In contrast, complex 2 deteriorated under measured conditions (pH 8.0–12.0) and formed NiOx composite active for WOR. The NiOx composite derived from 1 in 0.1 M PBS at pH 11.0 showed an activity with an overpotential of ~500 mV, a Tafel slope of ~90 mV/decade and a Faradaic efficiency of 97%. Mechanisms were proposed for water oxidation catalyzed by 1 and 2 . This work revealed that the catalytic activity of the nickel complexes was related to the flexibility of the tetrapyridyl ligands and the adaptability of the coordination sphere of the nickel(II) center. 相似文献
10.
The friction at the liquid-solid interfaces is widely involved in various phenomena ranging from nanometer to micrometer scales. By the molecular dynamic(MD)simulation, the friction properties of liquid-solid interfaces at the molecular level are calculated via the Green-Kubo relation. It is found that the system size will influence the value of the friction coefficient, especially for the solid surfaces with the larger polar charge. The value of the friction coefficient decreases with the increase in the system size and converges at large system sizes. The large polar charge will lead to a significant friction coefficient. However, the diffusion of water molecules on this surface is almost a constant, indicating that the diffusion coefficient seems to be independent of the system size and polar charge. This work provides insights for the selection of the system size in modeling the frictional properties of hydrophobic/hydrophilic surfaces. 相似文献